BIOL 221 Lecture_ch08_Skeletal System_2021 PDF

Andrews University BIOL 221-001 Chapter 08 The Skeletal System Axial Skeleton Frontal bone Parietal bone...

Andrews University BIOL 221-001 Chapter 08 The Skeletal System Axial Skeleton Frontal bone Parietal bone Axial skeleton is Skull Maxilla Occipital bone colored Beige Mandible Mandible Forms central Pectoral Clavicle girdle Scapula Clavicle Scapula supporting axis of body Thoracic Sternum Ribs Humerus Skull, vertebrae, cage Costal cartilages sternum, ribs, sacrum, and hyoid Vertebral column Pelvis Hip bone Appendicular skeleton Sacrum Ulna Coccyx Radius Carpus Metacarpal is colored Green Appendicular Skeleton bones Phalanges Pectoral girdle Femur Upper extremity Patella Pelvic girdle Lower extremity Fibula Tibia Metatarsal bones Tarsus Phalanges (a) Anterior view (b) Posterior view 1  Bones of the Skeletal System Number of bones – 206 in typical adult skeleton Varies with development of sesamoid bones – Bones that form within tendons (e.g., patella) Varies with presence of sutural (wormian) bones in skull – Extra bones that develop in skull suture lines – 270 bones at birth, but number decreases with fusion 8-2  Anatomical Features of Bones Bone markings— ridges, spines, bumps, depressions, canals, pores, slits, cavities, and articular surfaces Ways to study bones – Articulated skeleton: held together by wire and rods, shows spatial relationships between bones – Disarticulated bones: taken apart so their surface features can be studied in detail 8-3 8-4  Anatomical Features of Bones (c) Femur (d) Humerus Lines Crest (posterior view) (anterior view) Sinuses Fovea Foramen Head Crest Meatus Trochanters Head Process Tubercle Condyle Alveolus Spine Foramen Tuberosity (a) Skull (lateral view) Line Process Spine Fossae Epicondyles Fossae Condyles (b) Scapula (posterior view) Figure 8.2 8-5  The Skull Skull— most complex part of skeleton 22 bones joined together by sutures (immovable joints) Several cavities— cranial cavity (brain case), orbits (eye sockets), nasal cavity, oral (buccal) cavity, middle- and inner-ear cavities, and paranasal sinuses 8-6  The Skull Foramina— holes that allow passage for nerves and blood vessels Paranasal sinuses (4) — frontal, sphenoid, ethmoid, maxillary – Lined by mucous membrane and are air-filled – Act as chambers that add resonance to the voice; lighten the skull FSEM 8-7  The Skull Cranial cavity Frontal bone Ethmoid air cells Ethmoid bone Orbit Superior Zygomatic Nasal Middle bone conchae Inferior Maxilla Maxillary Vomer sinus Nasal cavity Oral Mandible cavity 8-8  Cranial Bones Figure 8.9 Anterior cranial fossa Frontal lobe Middle cranial Temporal lobe fossa Cerebellum Posterior cranial Posterior cranial fossa fossa Middle cranial fossa Anterior cranial fossa (a) Superior view (b) Lateral view Cranium (braincase) – Meninges (membranes) separate brain from bones - DAP Dura mater is thickest membrane; Arachnoid, Pia mater – Consists of two parts: calvaria (skullcap) and cranial base 8-9  Cranial Bones Anterior cranial fossa Frontal lobe Temporal lobe Middle cranial fossa Cerebellum Posterior cranial fossa Posterior cranial fossa Middle cranial fossa Anterior cranial fossa (a) Superior view Figure 8.9 (b) Lateral view Base is divided into three basins that comprise the cranial floor – Anterior cranial fossa holds the frontal lobe of the brain – Middle cranial fossa holds the temporal lobes of the brain – Posterior cranial fossa contains the cerebellum 8 cranial bones: 1 frontal, 2 parietal, 2 temporal, 1 occipital, 1 sphenoid, 1 ethmoid 8-10  The Frontal Bone Forms forehead and part of the roof of the cranium Coronal suture—posterior boundary of frontal bone Supraorbital margin—ridge of bone deep to eyebrow Supraorbital foramen provides passage for nerve, artery, and vein Glabella—smooth area above root of the nose Contains frontal sinus Figure 8.3 8-11 The Frontal Bone 8-12  The Parietal Bones Form most of cranial roof and part of its lateral walls Bordered by four sutures – Sagittal: between parietal bones Anterior – Coronal: at anterior margin Frontal bone – Lambdoid: at posterior margin Coronal suture – Squamous: at lateral border Parietal bone Sagittal suture Two temporal lines for Sutural bone attachment of the temporalis Parietal foramen muscle Lambdoid suture Occipital bone 8-13 Posterior  The Temporal Bones Temporal bone: lateral wall and part of floor of cranial cavity Four parts: squamous, tympanic, mastoid, and petrous 1. Squamous part – Encircled by squamous suture – Zygomatic process – Mandibular fossa 2. Tympanic part – External auditory meatus – Styloid process Figure 8.4a 3. Mastoid part – Mastoid process – Mastoid notch – Mastoid foramen – Stylomastoid foramen 8-14  The Temporal Bones (Continued) 4. Petrous part – Part of cranial floor – Separates middle from posterior cranial fossa – Houses middle- and inner-ear cavities – Receptors for hearing and balance – Internal auditory meatus— opening for CN VIII (vestibulocochlear nerve) – Carotid canal – Jugular foramen Figure 8.5b 8-15  The Temporal Bones (a) Lateral surface Squamous suture Squamous part Mastoid part Zygomatic process Mandibular fossa Mastoid notch External acoustic meatus Mastoid process Styloid process Tympanic part Squamous suture Squamous part Zygomatic Petrous part process Internal acoustic meatus Styloid process Mastoid process 8-16 (b) Medial surface  The Occipital Bone Rear and base of skull Foramen magnum opening for spinal cord Basilar part—thick median plate Occipital condyles—knobs resting on spinal column – Condylar canal, posterior to occipital condyle (only present in some people) Hypoglossal canal transmits hypoglossal nerve (CN XII) External occipital protuberance for nuchal ligament Superior and inferior nuchal lines for neck muscle attachment Figure 8.5a 8-17  The Sphenoid Bone Lesser wing Dorsum sellae Greater wing Superior orbital fissure Body Foramen Body Foramen ovale rotundum Lateral pterygoid plate Greater wing Medial pterygoid plate Pterygoid (b) Posterior view processes Lesser wing Figure 8.11b Optic canal Diploe (spongy bone) Crista galli Cribriform foramina Frontal bone Cribriform plate Anterior of ethmoid bone Optic foramen Sphenoid bone clinoid O Foramen rotundum Foramen ovale Sella turcica processes R Foramen spinosum Internal acoustic Temporal bone Petrous part of O meatus Jugular foramen temporal bone Parietal bone Foramen magnum Superior Groove for S venous sinus Hypoglossal canal Occipital bone orbital fissure Sella turcica (b) Superior view of cranial floor 8-18  The Sphenoid Bone Foramen rotundum Foramen ovale Figure 8.11a Foramen lacerum Posterior nasal apertures or choanae Medial and lateral pterygoid plates Sphenoid sinus 8-19 Figure 8.5b The Sphenoid Bone Figure 8.4b 8-20 The Sphenoid Bone 8-21  Sphenoid Foramina Optic canal Foramen rotundum O S R O S Superior orbital Foramen ovale fissure Foramen spinosum Photos © McGraw-Hill Education  Structures that pass foramina of Sphenoid Bone (SOROS) Superior Orbital Fissure Foramen Ovale (MALE) 1. Lacrimal nerve 1. Mandibular Nerve (CN V3) 2. Frontal nerve 2. Accessory meningeal nerve 3. Trochlear nerve 3. Lesser petrosal nerve 4. Occulomotor nerve 4. Emissary vein (Cavernous 5. Nasociliary nerve sinus to pterygoid plexus) 6. Abducent nerve Foramen Spinosum (MEN) 7. Superior ophthalmic vein 1. Middle meningeal artery and Foramen Rotundum vein (posterior trunk) 2. Emissay vein 1. Maxillary nerve (CN V2 3. Meningeal branch of Trigeminal) mandibular nerve 8-23  The Ethmoid Bone Located between eyes Contributes to medial Cribriform wall of orbit, walls and plate roof of nasal cavity, and Cribriform Crista galli nasal septum foramina Orbital plate Superior Perpendicular plate Ethmoidal nasal concha forms superior two-thirds cells Middle of nasal septum Perpendicular nasal concha Cribriform plate forms plate roof of nasal cavity Crista galli: blade, attachment for dura Cribriform (olfactory) foramina Figure 8.12 Labyrinth forms lateral masses - Ethmoidal cells - Orbital plate 8-25  The Ethmoid Bone Figure 8.4b Superior and middle nasal conchae— scroll-like plates that project into the nasal fossa Along with an inferior concha (a separate bone), these plates occupy most of the nasal cavity, create turbulence of airflow, and help humidify air 8-26 The Ethmoid Bone Figure 8.13 8-27  Bones that form the Eye Orbit F S F S Z E L M P M Figure 8.14 8-28  Ethmoid Bone Photos © McGraw-Hill Education  Crista galli Ethmoid Bone Ethmoid Ethmoid air air cells cells Middle nasal Perpendicular Orbital concha plate plate Photos © McGraw-Hill Education  Facial Bones Facial bones (14)—skull bones anterior to the cranial cavity (do not enclose brain) – Support teeth – Give shape to face – Form part of orbital and nasal cavities – Provide attachments for muscles of facial expression and mastication 2 maxillae 2 nasal bones 2 palatine bones 2 inferior nasal conchae 2 zygomatic bones 1 vomer 2 lacrimal bones 1 mandible 8-31  The Maxillae Largest facial bones Forms upper jaw and meets at median intermaxillary suture – Alveolar processes: bony points between teeth – Alveolus: sockets that hold teeth – Cleft palate and cleft lip occur when the two maxillae fail to join at the suture Figure 8.3 8-32 The Maxillae Figure 8.5a 8-33  The Maxillae (Continued) Forms inferomedial wall of orbit – Infraorbital foramen – Inferior orbital fissure Forms most of the hard palate – Forms roof of mouth and floor of nasal cavity – Palate allows us to chew while breathing – Palatine process – Incisive foramen 8-34  The Maxillae Sphenoid sinus Frontal sinus Ethmoid sinus Maxillary sinus Maxillary sinus fills maxillae bone Larger in volume than frontal, sphenoid, and ethmoid sinuses 8-35  The Palatine Bones L-shaped bones Form posterior portion of the hard palate Part of lateral nasal cavity wall Part of the orbital floor Greater palatine foramina 8-36  The Zygomatic Bones Form angles of cheekbones and part of each lateral orbital wall Zygomaticofacial foramen Zygomatic arch is formed from temporal process of zygomatic bone and zygomatic process of temporal Figure 8.4a bone 8-37 The Lacrimal Bones Form part of medial wall of each orbit Smallest bone of skull Lacrimal fossa houses lacrimal sac – Tears collect in sac and drain into nasal cavity Figure 8.4a 8-38  The Nasal Bones Form bridge of nose Support cartilages that Figure 8.3 shape lower portion of the nose Often fractured 8-39  The Inferior Nasal Conchae Inferior nasal concha is largest of three conchae in the nasal cavity – It is separate from the other conchae that are parts of the ethmoid bone Figure 8.13 8-40  The Vomer Inferior half of the nasal septum – Inferior to perpendicular plate of ethmoid Supports cartilage that forms anterior part of nasal septum Figure 8.4b 8-41  The Mandible Strongest bone of skull – Only one to noticeably move Supports lower teeth – Alveolar processes between teeth Provides attachments for muscles of expression and mastication Mental symphysis—joint at midline – Ossifies in early childhood – Mental protuberance—point of chin Mental foramen on anterolateral Figure 8.15 surface – For nerves and vessels of chin Mandibular foramen on medial surface – For nerves and vessels of lower teeth 8-42 The Mandible Major parts TMJ – Body: supports teeth – Ramus: articulates with cranium – Angle— where body meets ramus Features of ramus – Condylar process with mandibular condyle that articulates with temporal bone forming TMJ (temporomandibular joint) – Coronoid process for temporalis muscle – Mandibular notch between processes 8-43  Bones Associated with the Skull Auditory ossicles – Three in each middle-ear cavity – Malleus, incus, and stapes (MIS) Hyoid bone – Slender U-shaped bone Styloid process between chin and larynx Stylohyoid muscle – Does not articulate with any Hyoid Lesser other bone horn Larynx Greater – Suspended from styloid horn process of skull – Body and greater and lesser Body horns (cornua) Figure 8.16 – Fractured hyoid bone is evidence of strangulation 8-44  Auditory Ossicles (6) Photos © McGraw-Hill Education  The Skull in Infancy and Childhood Fontanels— spaces between Coronal suture unfused cranial bones Frontal Parietal bone bone Sphenoid – Contain fibrous membrane Lambdoid suture fontanel Nasal bone – Allow shifting of bones during Squamous suture Maxilla birth and growth of brain Occipital bone Mastoid Zygomatic bone – Anterior, posterior, Mandible fontanel Sphenoid sphenoid (anterolateral), and Temporal bone bone (a) Lateral view mastoid (posterolateral) fontanels Frontal bone Anterior fontanel Two frontal bones fuse by age 6 (metopic suture) Sagittal suture Skull approaches adult size Parietal bone Posterior fontanel by 8 or 9 years of age (b) Superior view Figure 8.17 8-46  The Vertebral Column and Thoracic Cage Expected Learning Outcomes – Describe the general features of the vertebral column and those of a typical vertebra. – Describe the structure of the intervertebral discs and their relationship to the vertebrae. – Describe the special features of vertebrae in different regions of the vertebral column, and discuss the functional significance of the regional differences. – Describe the anatomy of the sternum and ribs and how the ribs articulate with the thoracic vertebrae. 8-47  General Features of the Vertebral Column 33 Functions of spine Anterior view Posterior view Atlas (C1) – Supports skull and trunk and 7 Axis (C2) allows for their movement Cervical C7 vertebrae – Protects spinal cord T1 – Absorbs stresses of movements – Provides attachments for limbs, 12 thoracic cage, and postural Thoracic muscles vertebrae T12 33 vertebrae with intervertebral discs between L1 5 Lumbar most of them vertebrae – Discs account for about one- L5 quarter of spine’s 71 cm length (on average) S1 5 Sacrum – Discs compress a bit during the S5 day due to pressure of body Coccyx 4 Coccyx weight 8-48  General Features of the Vertebral Column Anterior view Posterior view Five vertebral groups Atlas (C1) Axis (C2) 7 Cervical – 7 cervical in the neck C7 vertebrae – 12 thoracic in the chest T1 – 5 lumbar in lower back 12 – 5 fused sacral at base of Thoracic vertebrae spine – 4 fused coccygeal T12 Variations in number of L1 5 Lumbar vertebrae occur in 1 in 20 vertebrae people L5 – Generally in the number of S1 fused vertebrae in inferior part 5 Sacrum of spine S5 Coccyx 4 Coccyx Figure 8.18 8-49  General Features of the Vertebral Column Primary curvature: spine exhibits one continuous C- shaped curve at birth (convex) – This persists as the curvature of the thoracic and pelvic spine With crawling and walking, secondary curvatures develop in cervical and lumbar areas (concave) – Vertebral column is S-shaped beyond the age of 3 years Figure 8.20 8-50 General Features of the Vertebral Column S-shaped vertebral column C1 Cervical curvature with four normal curvatures C7 T1 – Cervical- convex – Thoracic - concave Thoracic – Lumbar - convex curvature – Pelvic - concave T12 L1 Lumbar curvature L5 S1 Pelvic curvature 8-51  Abnormal Spinal Curvatures (a) Scoliosis Abnormalities result from lateral disease, paralysis of trunk curvature muscles, poor posture, thoracic pregnancy, or congenital curvature defects lumbar curvature Scoliosis— abnormal lateral curvature – Most common (b) Kyphosis (c) Lordosis – Usually in thoracic region (“hunchback”) (“swayback”) Key Normal – Particularly of adolescent girls Pathological Osteoporosis Pregnancy – Developmental abnormality in weight lifting or obesity which the body and arch fail to develop on one side of the vertebrae Figure 8.21 8-52  Vertebral Column with Scoliosis Photos © McGraw-Hill Education  Abnormal Spinal Curvatures Kyphosis (hunchback)— exaggerated thoracic curvature – Usually from osteoporosis, also osteomalacia or spinal tuberculosis, wrestling or weight lifting in young boys Lordosis (swayback)— exaggerated lumbar curvature – From pregnancy or obesity 8-54  General Structure of Vertebra Body (centrum) – Spongy bone (with red Posterior marrow) covered with a shell Spinous process of compact bone Superior articular Lamina – Weight-bearing portion facet – Rough surfaces enhance Vertebral Transverse arch process attachment of intervertebral Vertebral foramen Pedicle discs Vertebral foramina Body – Collectively form vertebral canal for spinal cord Anterior Vertebral arch Figure 8.22a – Pedicle: pillar-like – Lamina: plate-like Spinous process – Projects from arch – Bump that is visible under skin 8-55  General Structure of Vertebra Transverse process – Extends laterally from point where pedicel and lamina meet Superior articular processes – Project upward from one vertebra and meets inferior articular processes from the vertebra above Facets – Flat articular surfaces covered with hyaline cartilage Figure 8.23a 8-56  General Structure of Vertebra Superior articular process of L1 Intervertebral foramen Inferior vertebral – Opening between pedicles L1 notch of L1 of two adjoining vertebrae Intervertebral – Passageway for spinal foramen Superior vertebral nerves notch of L2 L2 – Inferior vertebral notch in Spinous process the pedicle of the upper Intervertebral disc vertebra – Superior vertebral notch L3 Inferior articular process of L3 in the pedicle of the lower (b) Left lateral view vertebra Figure 8.23b 8-57  Intervertebral Discs Intervertebral discs (23) – Pad consisting of: Nucleus pulposus— inner gelatinous mass ring of fibrocartilage – Bind vertebrae together – Support weight of the body – Absorb shock – Herniated disc (“ruptured” or “slipped” disc) puts painful pressure on spinal nerve or spinal cord Figure 8.22b,c 8-58  Regional Characteristics of Vertebrae Superior views Lateral views Spinous process Lamina Superior articular facet Transverse foramen Body Transverse process Spinous process (a) Cervical vertebrae Inferior articular Figure 8.25a process Cervical vertebrae (C1-C7) are small and light Bifid or forked spinous processes in C2 to C6 Small body and large vertebral foramen Transverse foramen in each short transverse process – Provides passage for vertebral artery and vertebral vein C1 = atlas; C2 = axis C7 = vertebra prominens— prominent spinous process 8-59  Cervical Vertebrae Atlas (C1) – Supports the head no body – Has no body; consists of delicate ring around large vertebral foramen – Lateral masses Superior articular facets articulate with occipital condyles forming atlanto– occipital joint; allows nodding “yes” Figure 8.24a Inferior articular facets articulate with C2 – Anterior and posterior arches Anterior and posterior tubercles 8-60  Cervical Vertebrae Axis (C2) – Allows head rotation gesturing “no” – Dens or odontoid process— prominent knob on its anterosuperior side Fuses with axis by age 3 to 6 years Projects into vertebral foramen of the atlas Held in place by a transverse ligament – Atlantoaxial joint: between Figure 8.24b atlas and axis 8-61  Atlas and Axis Articulation Axis of rotation Dens Atlas Transverse ligament Axis Figure 8.24c 8-62 (c) Atlantoaxial joint  The Thoracic Vertebrae Spinous process Superior articular facet Lamina Transverse process Transverse costal facet Superior costal facet Transverse costal facet Inferior costal facet Body Inferior articular facet (b) Thoracic vertebrae Spinous process Figure 8.25b 12 thoracic vertebrae (T1–T12) – Correspond to the 12 pairs of ribs attached to them Spinous processes pointed and angled sharply downward Have larger body than cervical, but smaller than lumbar Superior and inferior costal facets for attachment of ribs – On body as small, smooth, slightly concave spots Transverse costal facets at end of each transverse process T1–T10 – Provide second point of articulation for ribs 1–10 8-63  The Lumbar Vertebrae Spinous process Superior articular facet Superior articular process Transverse process Pedicle Body Spinous process (c) Lumbar vertebrae Figure 8.25c Inferior articular facet Five lumbar vertebrae (L1–L5) Thick, stout body Blunt, squarish spinous process Superior articular processes face medially – Lumbar region resistant to twisting movements 8-64  The Sacrum Sacrum— bony plate that forms posterior wall of pelvic cavity Five separate sacral vertebrae Superior articular process (S1–S5) begin fusing around Sacral age 16 and complete fusion by Ala promontory age 26 S1 Anterior surface S2 – Smooth and concave Transverse lines – Four transverse lines indicate Anterior sacral S3 regions of fusion foramina S4 – Four pairs of large anterior S5 sacral (pelvic) foramina Co2 Co1 Coccyx Co3 Co4 Allow passage of nerves and arteries to pelvic organs (a) Anterior view – Sacral promontory—ridge Figure 8.26a jutting from front of S1 8-65 The Sacrum (Continued) Posterior surface very rough – Median sacral crest— fusion of spinous processes Alae – Lateral sacral crests— fusion of transverse processes – Posterior sacral foramina— four pairs of openings for nerves to gluteal region and lower limbs Sacral canal runs vertically through sacrum and ends as sacral hiatus – Contains spinal nerve roots Auricular surface is part of sacroiliac (SI) joint formed with hip bone Superior articular processes on S1; Figure 8.26b articulates with L5 Alae— pair of large, wing-like extensions lateral to the superior articular processes 8-66  The Coccyx Coccyx—usually consists of four small vertebrae (Co1–Co4); sometimes five Superior articular Sacral canal process Fuse into single, triangular bone by age 20 Median sacral crest to 30 Auricular surface Horns (-0) on Co1 Lateral sacral – Serve as attachment points crest for ligaments that bind Posterior sacral foramina coccyx to sacrum Horn Sacral hiatus Fractured during difficult Transverse childbirth or by hard fall Provides attachment for process Coccyx (b) Posterior view muscles of the pelvic floor Figure 8.26b 8-67  The Thoracic Cage Thoracic cage consists of thoracic vertebrae, sternum, and ribs Encloses lungs and heart Sternoclavicular joint – Also provides some Acromioclavicular joint T1 Sternum: Suprasternal notch protection of spleen, liver 1 Clavicular notch kidneys Pectoral girdle: Clavicle Scapula 2 Manubrium Angle Provides attachment for 3 pectoral girdle and upper True ribs (1–7) 4 Body limbs 5 Xiphoid process Broad base, narrower 6 Costal cartilages apex 7 8 11 Rhythmically expanded Floating ribs (11–12) 9 12 T12 by respiratory muscles False ribs (8–12) 10 L1 Costal margin to draw air into lungs Costal margin— inferior Figure 8.27 border of thoracic cage formed by arc of lower ribs 8-68  The Sternum Sternum (breastbone)— bony plate anterior to the heart Divided into three regions – Manubrium Broad superior portion Suprasternal (jugular) notch Clavicular notches— articulate with clavicle – Body (gladiolus) Longest part of sternum Sternal angle— point where body joins manubrium Ribs attach along scalloped lateral margins – Xiphoid Inferior point of sternum Attachment for some abdominal muscles CPR (cardiopulmonary resuscitation) should avoid pressure against the xiphoid to avoid internal bleeding 8-69  The Ribs Sternoclavicular joint 12 pairs of ribs Acromioclavicular joint T1 Sternum: Suprasternal notch - Posterior (proximal) Pectoral girdle: Clavicle 1 Clavicular notch Manubrium ends attached to Scapula 2 Angle vertebral column 3 Body - Most ribs’ anterior 4 True ribs (1–7) (distal) ends attached 5 Xiphoid process to sternum Costal cartilages 6 Costal cartilages 7 11 8 (made of hyaline 12 T12 False ribs Floating ribs (8–12)(11–12) 9 10 L1 cartilage) attach rib Costal margin to sternum Figure 8.27 8-70  The Ribs Tubercle Neck Head Head— portion of rib that articulates with bodies of Articular facet Superior Inferior thoracic vertebrae Angle for transverse Articular facets process for vertebral bodies – Superior and inferior articular facets Neck— narrow portion distal Costal groove Shaft (b) Ribs 2–10 Figure 8.28b to the head Tubercle— wider, rough area distal to the neck Superior Transverse articular facet costal facet for rib 6 – Articulates with transverse costal facet of vertebra Tubercle Superior Rib 6 Neck costal facet Head T6 for rib 6 8-71 (b) Superior view Figure 8.29b  The Ribs Tubercle Neck Head Angle— lateral curve of rib Superior Inferior Shaft— long, gentle Articular facet Angle for transverse process Articular facets for vertebral bodies sloping, blade-like portion of rib Costal groove – Costal groove on inferior Shaft margin of shaft (b) Ribs 2–10 Figure 8.28b 8-72  The Ribs Inferior costal facet of T5 Vertebral Superior articular body T5 facet of rib 6 Rib 6 Inferior articular Vertebral facet of rib 6 body T6 Superior costal facet of T6 (a) Anterior view Superior Transverse articular costal facet facet for rib 6 Tubercle Superior Neck Rib 6 costal Head facet T6 for rib 6 Figure 8.29 8-73 (b) Superior view  The Ribs True ribs (ribs 1–7) – Each is directly connected to sternum False ribs (ribs 8–12) – Lack independent connections to sternum – Floating ribs (ribs 11–12) Do not have cartilaginous connection to sternum or higher costal Figure 8.27 cartilages Do not have tubercles or attachments to transverse processes of vertebra 8-74  The Pectoral Girdle and Upper Limb Expected Learning Outcome – Identify and describe the features of the clavicle, scapula, humerus, radius, ulna, and bones of the wrist and hand. 8-75  The Pectoral Girdle Pectoral girdle (shoulder girdle) supports the arm Consists of two bones on each side of the body – Clavicle (collarbone) and scapula (shoulder blade) Clavicle articulates medially to the sternum and laterally to the scapula – Sternoclavicular joint – Acromioclavicular joint Scapula articulates with the clavicle and the humerus – Glenohumeral joint: shoulder joint – Easily dislocated due to loose attachment 8-76  The Clavicle Sternal Acromial end Conoid tubercle end (a) Superior view Figure 8.30 Conoid tubercle Sternal end Acromial end (b) Inferior view Clavicle— S-shaped, somewhat flattened bone Sternal end— hammer-like head Acromial end— flattened Conoid tubercle— rough bump near acromial end Braces shoulder, keeps arm away from midline Frequently fractured 8-77  The Scapula Scapula— named for resemblance to a shovel Triangular plate that posteriorly overlies ribs 2 to 7 – Three sides: superior, medial, and lateral borders – Three angles: superior, inferior, and lateral angles Suprascapular notch—conspicuous notch on superior border – Provides passage for a nerve Spine—transverse ridge on posterior surface – Supraspinous fossa: indentation superior to the spine – Infraspinous fossa: broad surface inferior to the spine 8-78  The Scapula Subscapular fossa— concave, anterior surface of scapula Lateral angle of scapula has three main features – Acromion: plate-like extension of the spine Forms apex of the shoulder Articulates with clavicle— sole point of attachment of scapula and upper limb to the rest of the skeleton – Coracoid process: shaped like a bent finger Provides attachment for tendons of biceps brachii and other arm muscles – Glenoid cavity: shallow socket that articulates with the head of the humerus Helps form glenohumeral joint 8-79  (a) Anterior view (b) Posterior view Superior angle Suprascapular Superior notch 2nd border Acromion rib Acromion Supraspinous Coracoid fossa process Lateral angle Spine Glenoid cavity Subscapular Infraspinous fossa fossa Lateral Medial border border 7th rib Inferior angle P. 295 Humeroscapular (Glenohumeral) Joint >95% as anterior dislocation x axillary nerve/artery, x pulling on the arm of unconscious person  Spine Photos © McGraw-Hill Education  The Upper Limb Upper limb is divided into four regions containing a total of 30 bones per limb 1. Brachium (arm proper): extends from shoulder to elbow Contains only 1 bone— humerus 2. Antebrachium (forearm): extends from elbow to wrist Contains 2 bones— radius and ulna 3. Carpus (wrist) Contains 8 small bones arranged in two rows 4. Manus (hand) 19 bones in two groups – 5 metacarpals in palm – 14 phalanges in fingers 8-82 The Humerus Proximal end – Hemispherical head that articulates with the glenoid cavity of scapula – Anatomical neck – Greater and lesser tubercles and deltoid tuberosity – Intertubercular sulcus holds biceps tendon – Surgical neck 8-83 Figure 8.32  The Humerus Distal end – Rounded capitulum articulates with head of radius – Trochlea articulates with ulna – Lateral and medial epicondyles – Lateral and medial supracondylar ridges – Olecranon fossa holds RC O olecranon process of ulna ALCr PMTu – Coronoid fossa – Radial fossa 8-84  Humerus - Distal Median Coronoid epicondyle Trochlea fossa Capitulum Photos © McGraw-Hill Education  The Radius Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Olecranon Olecranon Radial notch Trochlear notch Radius Head of of ulna Head of radius – Head: disc-shaped, allows radius Coronoid process for rotation during pronation Neck of and supination Neck of radius Ulnar tuberosity radius Radial Superior surface tuberosity articulates with Ulna capitulum on humerus Side of disc spins on Radius radial notch on ulna Interosseous – Neck borders – Radial tuberosity for Interosseous biceps muscle membrane – Styloid process can be Ulnar notch palpated near thumb of radius – Ulnar notch Head of ulna accommodates head of Styloid process ulna Styloid Articular facets Styloid process process (a) Anterior view (b) Posterior view 8-86 Figure 8.33  The Ulna Olecranon Olecranon Radial notch Trochlear notch Ulna of ulna Head of Head of radius – Trochlear notch articulates Coronoid process radius Neck of Neck of with trochlea of humerus radius radius Ulnar tuberosity – Olecranon: bony point at Radial tuberosity back of elbow Ulna – Coronoid process – Radial notch holds head of Radius radius Interosseous borders – Styloid process Interosseous membrane Interosseous membrane – Ligament attaches radius to Ulnar notch of radius ulna along interosseous Head of ulna margin of each bone Styloid process Styloid Articular Styloid process facets process (a) Anterior view (b) Posterior view Figure 8.33 8-87  The Carpal Bones Eight bones form wrist – Allow movements of flexion, extension, abduction, and adduction Two rows (four bones each) – Proximal row: scaphoid, lunate, triquetrum, and pisiform (SLTP) Pisiform is a sesamoid developed by age 9 to12 in tendon of flexor carpi ulnaris muscle – Distal row: trapezium, trapezoid, capitate, and hamate (TTCH) 8-88 The Right Wrist and Hand Distal phalanx II Key to carpal bones Middle phalanx II Distal row Proximal row Proximal phalanx II III II Distal Head IV phalanx I Phalanges Body V Proximal Base phalanx I I Head Metacarpal Body First metacarpal bones Base Hamulus of hamate Trapezoid Hamate Carpal Pisiform Trapezium Capitate Carpal bones Triquetrum Lunate Scaphoid bones HCTT PTLS Figure 8.34a (a) Anterior view 8-89 The Metacarpal Bones and the Phalanges Metacarpals— bones of the palm – Metacarpal I proximal to base of thumb – Metacarpal V proximal to base of little finger – Proximal base, body, and distal head Phalanges— bones of the fingers – Thumb or pollex has two phalanges Proximal, distal phalanx – Fingers have three phalanges Proximal, middle, distal phalanx 8-90  The Pelvic Girdle and Lower Limb Expected Learning Outcomes – Identify and describe the features of the pelvic girdle, femur, patella, tibia, fibula, and bones of the foot. – Compare the anatomy of the male and female pelvic girdles and explain the functional significance of the differences. 8-91  The Pelvic Girdle Pelvic girdle— a ring composed of three bones – Two hip (coxal) bones, Iliac crest also called ossa coxae orIlium Iliac fossa innominate bones Anterior superior – One sacrum (also part of iliac spine Anterior inferior iliac spine vertebral column) Ischium Spine Body Pelvis— the pelvic Pubis Ramus Superior ramus girdle plus ligaments and Inferior ramus Body Pubic symphysis muscles that line the (a) Anterosuperior view pelvic cavity and form its Figure 8.35a floor 8-92  The Pelvic Girdle Sacroiliac joint—joins (a) Anterosuperior view coxal bone to vertebral column Iliac crest – Auricular surface of Iliac fossa Base of sacrum Ilium Sacroiliac ileum to auricular Anterior superior iliac spine joint Pelvic surface of sacrum surface of sacrum Anterior inferior iliac spine Spine Pelvic inlet Coccyx Ischium Acetabulum Body Interpubic Pubic symphysis—the disc Ramus Superior ramus Obturator Pubis Inferior ramus foramen Body interpubic disc (of Pubic symphysis fibrocartilage) joins pubic bones anteriorly Figure 8.35a 8-93  The Pelvic Girdle Iliac crest Iliac fossa Base of Ilium sacrum Anterior Sacroiliac joint superior Pelvic surface iliac spine of sacrum Anterior inferior iliac spine Pelvic inlet Spine Coccyx Ischium Acetabulum Body Interpubic disc Ramus Superior ramus Obturator Pubis Inferior ramus foramen Body Pubic symphysis (a) Anterosuperior view Figure 8.35a Figure 8.35b Greater (false) pelvis— between flare of the hips Lesser (true) pelvis— narrower and below Pelvic brim— round margin that separates the two Pelvic inlet— opening circumscribed by brim that infant’s head must pass during birth Pelvic outlet— lower margin of the lesser pelvis 8-94  The Pelvic Girdle Three distinct features of hip bone – Iliac crest: superior crest Ilium Iliac crest of hip – Acetabulum: hip socket Anterior gluteal line Inferior gluteal – Obturator foramen: line Posterior gluteal Anterior superior iliac spine line large hole below Posterior superior Iliac spine acetabulum Posterior inferior Iliac spine r Anterior inferior iliac spine Greater sciatic notch Body of ilium Each adult hip bone is Acetabulum Pubis Superior ramus of pubis Ischial spine Body of pubis formed by the fusion Lesser sciatic notch Body of ischium Inferior ramus of pubis of three childhood Ischial tuberosity Obturator Ramus of ischium bones: ilium, ischium, Ischium foramen pubis Figure 8.36a (a) Lateral view  The Pelvic Girdle Ilium – Largest bone in hip – Extends from iliac crest to center of the acetabulum – Anterior and posterior superior spine – Anterior and posterior inferior spines – Greater sciatic notch and iliac fossa Ischium – Inferioposterior portion of hip – Heavy body with prominent spine – Lesser sciatic notch – Ischial tuberosity – Ramus Pubis (pubic bone) – Most anterior portion of the hip bone – Body, superior, and inferior ramus 8-96  The Pelvic Girdle Iliac Iliac crest fossa Obturator Ant. inf. foramen Ant. inf. iliac spine Photos © McGraw-Hill Education iliac spine  The Pelvic Girdle Figure 8.37 Male— heavier and thicker Female— wider and shallower, and adapted to the needs of pregnancy and childbirth, larger pelvic inlet and outlet for passage of infant’s head 8-99  The Lower Limb Lower limb divided into four regions containing 30 bones per limb – Femoral region (thigh): extends from hip to knee region Contains femur and patella – Crural region (leg proper): extends from knee to ankle Contains medial tibia and lateral fibula – Tarsal region (tarsus): ankle— the union of the crural region with the foot Tarsal bones are considered part of the foot – Pedal region (pes): foot Composed of 7 tarsal bones, 5 metatarsals, and 14 phalanges in the toes 8-100  The Femur Fovea capitis Longest and strongest bone Greater trochanter Greater trochanter of the body Head Neck Hemispherical head articulates Intertrochanteric Intertrochanteric line Lesser trochanter crest with acetabulum of pelvis Gluteal tuberosity Spiral line – Fovea capitis: pit in head of femur for attachment of a Linea aspera ligament Shaft Greater and lesser trochanters for muscle attachment Medial supracondylar Lateral Supracondylar Intertrochanteric crest— thick Lateral line line ridge on posterior surface that epicondyle Popliteal surface Lateral epicondyle connects the trochanters Patellar Medial epicondyle Lateral condyle surface Medial condyle Intertrochanteric line— more Intercondylar fossa Base of patella Articular facets delicate ridge on anterior Apex of patella surface that connects (a) Anterior view (b) Posterior view trochanters 8-101  The Femur Fovea capitis Greater trochanter Greater trochanter Head Neck Intertrochanteric Linea aspera—ridge on Intertrochanteric line Lesser trochanter crest posterior of the shaft Spiral line Gluteal tuberosity Spiral (pectineal) line and Linea aspera gluteal tuberosity Shaft Medial and lateral condyles and epicondyles found distally Medial Lateral Supracondylar supracondylar Lateral line line Intercondylar fossa epicondyle Popliteal surface Lateral epicondyle Patellar Medial epicondyle Lateral condyle Patellar and popliteal surface Medial condyle Intercondylar fossa surface Base of patella Articular facets Apex of patella (a) Anterior view (b) Posterior view 8-102  The Patella & Femur Fovea capitis Greater trochanter Greater trochanter Head Patella— triangular sesamoid Intertrochanteric Neck Intertrochanteric bone embedded in tendon of Lesser trochanter crest line Gluteal tuberosity knee Spiral line Cartilaginous at birth Linea aspera – Ossifies at age 3 to 6 years Shaft Base— broad, superior portion Apex— pointed, inferior Medial Lateral portion Supracondylar supracondylar Lateral line line Articular facets— shallow, epicondyle Popliteal surface Medial epicondyle Lateral epicondyle posterior portion Patellar Lateral condyle surface Medial condyle Intercondylar Quadriceps tendon extends fossa Base of patella Articular facets from front of thigh to patella Apex of patella – Continues as the patellar (a) Anterior view (b) Posterior view ligament from patella to tibia 8-103  Tibia Tibia— thick, medial, leg bone – Only weight-bearing bone of the crural region – Medial and lateral condyles Flat surfaces that articulate with condyles of femur – Intercondylar eminence— ridge separating condyles – Tibial tuberosity— attachment of patellar ligament, a continuation of quadriceps tendon – Anterior border— sharp, angular – Medial malleolus— bony knob on inside of ankle Figure 8.39 8-104 The Fibula Fibula— slender, lateral strut that helps stabilize ankle Does not bear any body weight Head— proximal end – Apex—point of the head Lateral malleolus— distal expansion, bony knob on lateral side of ankle Joined to tibia by interosseous membrane 8-105  Tarsal bones— in ankle The Ankle and Foot – Differ from carpal bones due to load-bearing role of the ankle Calcaneus— largest tarsal bone – Forms heel Distal phalanx I – Distal portion is point of Distal attachment for calcaneal Proximal phalanx V phalanx I (Achilles) tendon Middle phalanx V T Talus is most superior tarsal bone Metatarsal I II III Proximal phalanx V N C – Forms ankle joint with tibia and IV Medial cuneiform V CCCC fibula Lateral cuneiform Intermediate cuneiform – Sits upon calcaneus and Navicular Cuboid articulates with navicular Talus Calcaneus Proximal row of tarsal bones Trochlear Key to tarsal bones Distal – Talus, calcaneus, navicular surface Distal row of tarsal bones group Proximal group of talus Tuberosity of calcaneus – Medial, intermediate, lateral cuneiforms and cuboid (a) Superior (dorsal) view Figure 8.40a 8-106  The Ankle and Foot The rest of the foot bones resemble the hand bones in name and arrangement Distal phalanx I Metatarsals Distal Proximal phalanx V – Metatarsal I is proximal to phalanx I Middle the great toe (hallux) Metatarsal phalanx V – Metatarsal V is proximal to Proximal I II III phalanx V CCCC the little toe IV Medial cuneiform V NC – Proximal base, Lateral cuneiform Intermediate intermediate shaft, and cuneiform T distal head Navicular Cuboid Talus Calcaneus Phalanges – Two in great toe Key to tarsal Trochlear bones Distal surface group of talus Tuberosity of Proximal group Proximal and distal calcaneus phalanx – Three in all other toes (a) Superior (dorsal) view Proximal, middle, distal Figure 8.40a phalanx 8-107  The Ankle and Foot Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Thumb Future thumb Elbow Future Knee great toe Great toe (a) Seven weeks (b) Eight weeks Figure 8.41 Rotation of upper and lower limbs in opposite directions – Starts seventh week of embryonic development – Largest digit medial in foot and lateral in hand – Each limb rotates about 90° in opposite directions – Rotation also explains why elbow flexes posteriorly and knee flexes anteriorly 8-108  The Ankle and Foot Sole of foot is not flat on ground Three springy arches absorb stress 1. Medial longitudinal arch From heel to hallux 1. Medial Formed from the longitudinal arch calcaneus, talus, navicular, Transverse cuneiforms, and arch metatarsals I and III 2. Lateral 2. Lateral longitudinal arch longitudinal arch – From heel to little toe – Includes calcaneus, cuboid, and metatarsals IV and V Figure 8.42a (a) Inferior (plantar) view 8-109  The Ankle and Foot 3. Transverse arch – Across middle of foot – Includes the cuboid, cuneiforms, and proximal heads of metatarsals Medial longitudinal arch – Arches held together by 3. Transverse short, strong ligaments arch Lateral Pes planus (flat feet)— longitudinal arch excessive weight, repetitious stress, or congenital weakness